Capacitor

ABSTRACT

A capacitor includes: a capacitor element; an electrolyte impregnated into at least the capacitor element; a bottomed cylindrical metal case accommodating the capacitor element and the electrolyte; and a sealing body sealing an opening portion of the case. Further, the capacitor also includes a coating layer provided at a portion in contact with the outer surface of the sealing body and formed by dispersing, into resin, an adsorbent adsorbing a solvent included in the electrolyte. Alternatively, the sealing body is formed by dispersing the above-described adsorbent in a rubber component.

TECHNICAL FIELD

The present invention relates to capacitors that are used in varioustypes of electronic equipment, electrical equipment, industrialequipment, and automotive equipment, in particular, to capacitors usingan electrolyte.

BACKGROUND ART

FIG. 8 is a cross-sectional view showing a configuration of an aluminumelectrolytic condenser as an example of a conventional capacitor usingan electrolyte solution. The condenser includes capacitor element 20, anelectrolyte (not shown) which is impregnated into capacitor element 20,and metal case 21 in which these are accommodated. A pair of lead wires22 is drawn out from capacitor element 20. Lead wires 22 pass throughthrough hole 23A of sealing body 23 provided in the opening of case 21and are drawn out to the outside. Sealing body 23 is pressed by thedrawing process in the vicinity of the opening portion of case 21 andthe curling process of the opening end portion, whereby the openingportion of case 21 is sealed.

Insulating plate 24 is provided at a side of an end of the opening ofcase 21. Lead wires 22 drawn out to the outside through sealing body 23are inserted into the through hole provided in insulating plate 24, andbent along insulating plate 24. In this manner, the condenser may besurface-mounted on a printed circuit board.

In order to improve the mounting on the printed circuit board, sealingbody 23 is formed of vulcanized butyl rubber peroxide. The Young'smodulus of the vulcanized butyl rubber peroxide is 4 N/mm² or more at atemperature (250° C.) of a soldering temperature (230° C.) or more.Thus, even though the solder reflow conditions are increasingly hot atthe time of mounting on the printed circuit board, sealing body 23 nolonger expands (Patent Literature 1).

FIG. 9 is a cross-sectional view showing a configuration of anotherconventional aluminum electrolytic condenser. In this condenser,capacitor element 20 impregnated with electrolyte is accommodated incase 21 formed of aluminum. Then, lead wires 22 derived from capacitorelement 20 pass through a through hole provided in sealing body 23 madeof butyl rubber and are drawn out to the outside. Sealing body 23 isplaced in the opening portion of case 21, and is pressed by the drawingprocess. The sealing structure is configured in this manner.

Polyimide layer 30 is formed at the end surface (including the uppersurface of sealing body 23 and curling processing unit 29) of thecondenser main body of the aluminum electrolytic condenser. Polyimidelayer 30 is formed by applying, in a dropwise manner using a dispenser,an N-methyl-2-pyrrolidone solution (non-photosensitive) of polyamideacid 20 wt %, which is a polyimide precursor solution, and drying for 1hour at 125° C.

By forming polyimide layer 30 at an end surface of the condenser mainbody in this manner, thermal oxidation from the surface of sealing body23 is suppressed. Therefore, it is possible for sealing body 23 towithstand temperatures of 150° C. or more for long periods of time, andreduction of the electrolyte is greatly suppressed. As a result, it ispossible to suppress deterioration of the electrical characteristics ofthe condenser (Patent Literature 2).

However, when the above-described related aluminum electrolyticcondenser is used in a high temperature environment, a solvent componentincluded in the electrolyte is vaporized, and the vaporized solventcomponent is diffused to permeate sealing body 23 and escape to theoutside. Therefore, the functions of the electrolyte can no longer beperformed and the characteristics of the condenser deteriorate.Hereinafter, this issue will be referred to as “dry up”.

In order to reduce dry up, butyl rubber having a low solvent gaspermeability is used as the material of sealing body 23. However, evenwhen using butyl rubber as sealing body 23, the solvent gas generated incase 21 permeates sealing body 23 and escapes to the outside (into theatmosphere) at a certain ratio. Therefore, when used in a hightemperature environment for a long period of time, it is not possible toavoid the occurrence of dry up.

CITATION LIST Patent Literature

PTL 1 Japanese Patent Unexamined Publication No. 9-275045

PTL 2 Japanese Patent Unexamined Publication No. 2009-88277

SUMMARY OF THE INVENTION

The present invention is a capacitor which suppresses dry up bysuppressing solvent gas permeation of the sealing body, and whichexhibits a stable performance.

The capacitor of the present invention includes: a capacitor element; anelectrolyte which impregnated at least into the capacitor element; abottomed cylindrical metal case accommodating the capacitor element andthe electrolyte; and a sealing body sealing an opening portion of thecase. Further, the capacitor also includes a coating layer provided at aportion in contact with the outer surface of the sealing body and formedby dispersing an adsorbent in resin, which adsorbent adsorbing a solventincluded in the electrolyte. Alternatively, the sealing body is formedby dispersing the above-described adsorbent in a rubber component.

Dry up is thought to occur because the solvent gas permeates from theside of the case interior where the concentration is high to the side ofthe exterior where the concentration is low due to the fact that thereis a difference in the concentration of the solvent gas between the caseinterior side and the exterior side of the sealing body in contact withthe atmosphere. In contrast, in the capacitor according to the presentinvention, an adsorbent adsorbing the solvent gas is dispersed in thecoating layer or the sealing body itself. According to eitherconfiguration, the coating layer or the sealing body adsorbs the solventgas generated in the case interior. Therefore, the difference in theconcentration of the solvent gas in the metal case interior side and theexterior side of the sealing body becomes small, the solvent gaspermeation of the sealing body is thereby suppressed, and it is possibleto suppress dry up.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view showing the configuration of thecapacitor according to embodiment 1 of the invention.

FIG. 2 is a schematic enlarged cross-sectional view of a coating layerprovided on the capacitor shown in FIG. 1.

FIG. 3 is a characteristic diagram showing the remaining percentage byweight of the electrolyte according to the capacitor shown in FIG. 1 incomparison with comparative examples.

FIG. 4 is a cross-sectional view showing the configuration of thecapacitor according to embodiment 2 of the invention.

FIG. 5 is a schematic cross-sectional view of the sealing body used inthe capacitor shown in FIG. 4.

FIG. 6 is a schematic cross-sectional view of another sealing body usedin the capacitor shown in FIG. 4.

FIG. 7 is a characteristic diagram showing the remaining percentages byweight of the electrolyte according to the capacitor shown in FIG. 4 incomparison with a comparative example.

FIG. 8 is a cross-sectional view showing a configuration of aconventional aluminum electrolytic condenser.

FIG. 9 is a cross-sectional view showing a configuration of anotherconventional aluminum electrolytic condenser.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the drawings. In addition, where the configuration ofembodiment 2 is the same as that of embodiment 1, the same referencenumerals will be applied in the description and a detailed descriptionthereof may be omitted. Further, the present invention is not limited bythe respective embodiments.

First Exemplary Embodiment

FIG. 1 is a cross-sectional view showing the configuration of thecapacitor according to embodiment 1 of the invention, and FIG. 2 is aschematic enlarged cross-sectional view of a coating layer provided onthe capacitor. The capacitor includes: capacitor element 1, electrolyte4 impregnated into at least capacitor element 1; bottomed cylindricalmetal case 5; sealing body 6; and coating layer 7. Capacitor element 1is configured by winding an anode foil and cathode foil (not shown)through a separator made of cellulose. The anode foil is produced byforming a dielectric oxide film by an anodic oxidation process aftercarrying out an etching process on aluminum foil and roughening thesurface thereof. The cathode foil is produced by carrying out an etchingprocess on aluminum foil and roughening the surface thereof. Anode leadwire 2 is connected to the anode foil and cathode lead wire 3 isconnected to the cathode foil. Anode lead wire 2 and cathode lead wire 3are drawn out from capacitor element 1.

Capacitor element 1 configured in this manner is accommodated incylindrical bottomed metal case 5 made of aluminum after beingimpregnated with electrolyte 4.

Sealing body 6 seals the opening portion of case 5. Holes into whichanode lead wire 2 and cathode lead wire 3 are inserted are formed insealing body 6. After arranging sealing body 6 in the opening portion ofcase 5, a process of drawing the outer circumference of case 5 to theinner side is performed and case 5 is sealed by performing a curlingprocess on the opening edge of case 5. Sealing body 6 may have aconfiguration of butyl rubber, ethylene propylene (EPT) rubber, fluorinerubber, silicone rubber, nitrile rubber, or the like; however, it is notparticularly limited as long as the insulating material can seal case 5by being compressed.

Coating layer 7 is provided in a portion in contact with the outersurface of sealing body 6. Coating layer 7 is formed by dispersingadsorbent 9 adsorbing a solvent included in electrolyte 4 in resin 8. Inthis configuration, the solvent gas generated inside case 5 andpermeating sealing body 6 is adsorbed by adsorbent 9 mixed in coatinglayer 7 and the concentration of the solvent gas of coating layer 7becomes high. Therefore, the difference in the solvent gasconcentrations in the inside and outside of case 5 of sealing body 6becomes small. That is, the solvent gas concentration gradient in theinside and outside of case 5 of sealing body 6 becomes smooth. In thismanner, it is possible to suppress the permeation of the solvent gasinto sealing body 6.

As adsorbent 9, activated carbon, a molecular sieve (a kind ofcrystalline zeolite among zeolites) , zeolite (a generic term foraluminosilicate with fine pores in the crystal) , silica gel, and thelike, or any material having solvent gas adsorbability may be used.

The BET specific surface area of adsorbent 9 is 500 m²/g or more and3000 m²/g or less, and the average pore diameter is 0.5 nm or more and20 nm or less, more preferably, the specific surface area of adsorbent 9is 1000 m²/g or more and 3000 m²/g or less, and the average porediameter is 0.5 nm or more and 5 nm or less. Further, thecharacteristics of adsorbent 9 such as the material, specific surfacearea, and average pore diameter are preferably appropriately selectedaccording to the solvent used in electrolyte 4.

As resin 8 configuring coating layer 7, epoxy resin, fluorine resin,acrylic resin, polyimide resin, silicone resin, phenol resin, melamineresin, urethane resin, unsaturated polyester resins, and the like may beused. Besides these, as long as the material is capable of dispersingadsorbent 9 and forming coating layer 7, any material maybe used. Inaddition, in coating layer 7, in addition to adsorbent 9, an inorganicfiller or an organic filler may be dispersed as a filler.

When the mixing ratio of adsorbent 9 becomes small, the effect isweakened, conversely, when the mixing ratio is large, the mixing withresin 8 becomes difficult. Therefore, the mixing ratio of adsorbent 9 ispreferably in a range of 10 parts by weight or more and 80 parts byweight or less with respect to 100 parts by weight of resin 8.Alternatively, the mixing ratio of adsorbent 9 is preferably in therange of 6% by volume or more and 33% by volume or less of coating layer7.

Next, the effects of the embodiment will be described using specificexamples. When electrolyte 4 includes γ-butyrolactone as a main solvent,epoxy resin may be applied as resin 8, and activated carbon may beapplied as adsorbent 9. A ratio of 30 parts by weight of activatedcarbon to 100 parts by weight of epoxy resin is set. At this time, themixing ratio of activated carbon in coating layer 7 is 15% by volume.Coating layer 7 is formed by curing after the liquid in which theactivated carbon is dispersed in the epoxy resin at this ratio is coatedon the portion in contact with the outer surface of sealing body 6. Thethickness of coating layer 7 is approximately 200 μm. The specificsurface area of the activated carbon is 2300 m²/g, the average porediameter is 2 nm, and the average particle diameter is 3 μm. Thecomposition of electrolyte solution 4 is 75 parts by weight ofγ-butyrolactone, 25 parts by weight of 1,2,3,4 tetra methylimidazoliumphthalate, 0.5 parts by weight of nitrobenzoic acid, and 0.5 parts byweight of orthophosphate. The diameter of case 5 is 10 mm, and theheight is 9.5 mm. Sealing body 6 is butyl rubber with a thickness ofabout 2.7 mm. The capacitor configured in this manner is set as sampleE1.

For comparison with sample E1, sample C1 was prepared in the same manneras sample E1 except that coating layer 7 was not provided on the portionin contact with the outer surface of the sealing body. Further, sampleC2 was prepared in the same manner as sample E1 except that an epoxyresin layer not including activated carbon was formed instead of coatinglayer 7.

Samples E1, C1, and C2 prepared in this manner were put in a hightemperature tank at 135° C., the decreased state of electrolyte 4 overtime was measured and the results are shown in FIG. 3. FIG. 3 is acharacteristic diagram showing the remaining percentage by weight ofelectrolyte 4 over time.

As is clear from FIG. 3, in sample C1 and sample C2, the weight ofelectrolyte 4 is reduced over time. After 1000 hours, there was areduction of about 28% and the remaining weight was about 72%. This isbecause electrolyte 4 is reduced due to the γ-butyrolactone in gasifiedelectrolyte 4 permeating sealing body 6 and escaping to the outside. Onthe other hand, in sample E1, the weight of electrolyte 4 was reduced byabout 23% and the remaining amount stayed at about 77%, whereby it canbe understood that there is an effect of suppressing a reduction ofelectrolyte 4. Furthermore, when only a short time passes, there isalmost no difference between the weight reduction rates. This isconsidered to be because a certain time is needed until the activatedcarbon, which is adsorbent 9, adsorbs the solvent gas and the solventgas concentration in coating layer 7 becomes high.

Second Exemplary Embodiment

FIG. 4 is a cross-sectional view showing the configuration of thecapacitor according to embodiment 2 of the invention and FIG. 5 is aschematic cross-sectional view of the sealing body used in thecapacitor. The point of difference between the capacitor in thisembodiment and the capacitor of embodiment 1 is that the capacitor hassealing body 15 instead of sealing body 6 and coating layer 7. Sincethis embodiment is the same as embodiment 1 in other respects, detaileddescription thereof will be omitted.

Sealing body 15 is formed by dispersing adsorbent 9, which adsorbs thesolvent included in electrolyte 4 which impregnated into capacitorelement 1, in rubber component 16. This configuration exhibits effectssimilar to those of the embodiment 1. That is, the solvent gas generatedinside case 5 and permeating the inside of sealing body 15 is adsorbedby adsorbent 9 dispersed in sealing body 15, whereby the solvent gasadsorption concentration of the sealing body 15 becomes high. Therefore,the difference in the solvent gas concentrations in the interior andexterior of case 5 of sealing body 15 becomes small. In this manner, itis possible to suppress the solvent gas permeate sealing body 15.

As adsorbent 9, as in embodiment 1, activated carbon, molecular sieves,zeolites, silica gel, and the like, or any material having solvent gasadsorbability may be used.

As rubber component 16 configuring sealing body 15, butyl rubber,ethylene propylene (EPT) rubber, fluorine rubber, silicone rubber,nitrile rubber, acrylic rubber or the like may be used. Other thanthese, as long as the material is capable of dispersing adsorbent 9 andthe insulating material can seal case 5 by being compressed, there is noparticular limitation. Furthermore, in rubber component 16, in additionto adsorbent 9, fillers such as inorganic fillers, organic fillers, andthe like, or reinforcing materials such as carbon black, silica, and thelike may be dispersed.

When the mixing ratio of adsorbent 9 becomes small, the effect isweakened, conversely, when the mixing ratio of adsorbent 9 becomeslarge, the mixing of rubber component 16 becomes difficult. In addition,as the mixing ratio of adsorbent 9 becomes great, the modulus ofelasticity as sealing body 15 is deteriorated and the sealing functionis deteriorated. Therefore, the mixing ratio of adsorbent 9 ispreferably in a range of 10 parts by weight or more and 80 parts byweight or less with respect to 100 parts by weight of the butyl polymerin rubber component 16. Alternatively, the mixing ratio of adsorbent 9is preferably in a range of 8% by volume or more and 40% by volume orless of rubber component 16.

If the average particle diameter of adsorbent 9 is too large, it becomesdifficult to apply compressive stress evenly to sealing body 15 at thetime of sealing, and the reliability of the sealing is deteriorated. Onthe other hand, if the average particle diameter of adsorbent 9 is toosmall, dispersal defects are generated at the time of the rubber mixing.Therefore, the average particle diameter of adsorbent 9 is preferably 1μm or more and 100 μm or less.

Sealing body 15A shown in FIG. 6 may be used instead of sealing body 15.Sealing body 15A is configured of first layer 18 formed by rubbercomponent 16 including adsorbent 9, and second layer 19 formed by rubbercomponent 16 not including adsorbent 9. Sealing body 15A is arranged sothat first layer 18 becomes the upper side in FIG. 4.

When the solvent gas concentration of second layer 19 near the solventbecomes high, the solvent gas moves toward first layer 18 and permeatesto the outside. However, since first layer 18 includes adsorbent 9, thesolvent gas is adsorbed in first layer 18. Therefore, the solvent gasconcentration increases in first layer 18. Accordingly, it is possibleto reduce the difference between the solvent gas concentration of secondlayer 19 near the solvent and the solvent gas concentration of firstlayer 18 apart from the solvent. Therefore, even if adsorbent 9 was onlyincluded in first layer 18, it is possible to deteriorate the permeationof the solvent gas with good efficiency.

When adsorbent 9 is dispersed throughout sealing body 15 as shown inFIG. 5, the modulus of elasticity may be deteriorated by condition ofthe rubber mixing. When the modulus of elasticity is deteriorated, thereliability of the sealing is deteriorated. However, as shown in FIG. 6,by using sealing body 15A configured by first layer 18 and second layer19, it becomes possible to perform rubber mixing to raise the modulus ofelasticity of second layer 19 not including adsorbent 9. As a result,the sealing reliability in sealing body 15A is improved.

Adsorbent 9 may also be dispersed in second layer 19. In that case,adsorbent 9 may be dispersed to a greater degree in first layer 18 thanin second layer 19. In this manner, sealing body 15A includes firstlayer 18 facing the outside of the capacitor and second layer 19 facingthe inside of case 5, and adsorbent 9 is dispersed to a greater degreein first layer 18 than in second layer 19.

It is possible for adsorbent 9 to be mixed and the sealing body formedso that the content of adsorbent 9 is increased from the side facing theinside of case 5 toward the side facing the outer surface of thecapacitor.

Next, the effects of the embodiments will be described using specificexamples. When electrolyte 4 includes γ-butyrolactone as a main solvent,butyl rubber may be applied as rubber component 16, and activated carbonmay be applied as adsorbent 9. A ratio of 30 parts by weight ofactivated carbon to 100 parts by weight of butyl polymer is set. At thistime, the ratio of activated carbon in rubber component 16 is 15% byvolume. Sealing body 15 is formed by forming a mixture in which theactivated carbon is mixed and dispersed in the butyl rubber at thisratio. The thickness of sealing body 15 is approximately 2.7 mm. Thespecific surface area of the activated carbon is 2300 m²/g, the averagepore diameter is 2 nm, and the average particle diameter is 3 μm. Thecomposition of electrolyte solution 4 is 75 parts by weight ofγ-butyrolactone, 25 parts by weight of 1,2,3,4 tetra methylimidazoliumphthalate, 0.5 parts by weight of nitrobenzoic acid, and 0.5 parts byweight of orthophosphate. The diameter of case 5 is 10 mm, and theheight is 9.5 mm. The capacitor configured in this manner is set assample E2.

Sealing body 15A of the configuration shown in FIG. 6 is prepared in thefollowing manner. A rubber sheet for use as an outer layer beforecross-linking in which activated carbon which is adsorbent 9 is mixedand a rubber sheet for use as an inner layer before cross-linking inwhich activated carbon is not mixed are placed into a metal mold, heatedfor 10 to 20 minutes at 150 to 200° C., and bonded. Next, a laminatedbody of the rubber sheet for use as an outer layer and the rubber sheetfor use as an inner layer is taken out from the metal mold, heated forseveral hours at around 200° C. and integrated. The integrated rubbersheet is formed into a predetermined shape by a pressing process andforms sealing body 15A. Here, in the rubber sheet for use as an outerlayer, the same rubber sheet components are used as above-describedsealing body 15 and, in the rubber sheet for use as an inner layer, arubber sheet formed only of butyl rubber is used. Other than usingsealing body 15A, sample E3 capacitor is produced in the same manner assample E2.

Sample E4 is produced in the same manner as sample E2 except that theinside and outside of sealing body 15A of sample E3 are reversed and thesample is used with first layer 18 arranged on the inside and secondlayer 19 arranged on the outside.

For comparison with samples E2, E3, and E4, sample C3 is produced in thesame manner as sample E2 apart from using a sealing body formed only ofbutyl rubber. That is, sample C3 has the same configuration as sample C1of embodiment 1.

Samples E2, E3, E4 and C3 produced in this manner are put in a hightemperature tank at 135° C., the decreased state of electrolyte 4 overtime is measured and the results are shown in FIG. 7. FIG. 7 is acharacteristic diagram showing the remaining percentages by weight ofelectrolyte 4 over time.

As is clear from FIG. 7, in sample C3, the weight of electrolyte 4 isreduced over time. After 1000 hours, there is a reduction of about 26%and the remaining weight was about 74%. This is because electrolyte 4 isreduced due to the γ-butyrolactone in gasified electrolyte 4 permeatingsealing body 6 and escaping to the outside. On the other hand, in sampleE2, the weight of electrolyte 4 is reduced by about 18% and theremaining amount stayed at about 82%, whereby it can be understood thatthere is an effect of suppressing a reduction of electrolyte 4.

Even in sample E3 which used sealing body 15A in which activated carbonis mixed only in first layer 18 of the outer side, the weight ofelectrolyte 4 is reduced by about 18% and the remaining amount stayed atabout 82%, whereby it can be understood that there is an effect ofsuppressing a reduction of electrolyte 4. That is, sample E3 exhibitsalmost the same remaining percentage by weight of the electrolyte assample E2 which used sealing body 15 in which activated carbon isdispersed throughout.

As shown in sample E4, when activated carbon is included only in firstlayer 18 arranged on the inside, the weight reduction rate of theelectrolyte is about 21% and the remaining percentage is about 79%. Evenin this configuration, the weight reduction rate of the electrolyte isdecreased further than sample C3. However, compared to sample E3, theweight reduction rate of the electrolyte is increased. This isconsidered to be because the difference in the solvent gas concentrationbetween inside first layer 18 and outside second layer 19 becomes great,and the solvent gas gradually permeates to second layer 19 with a lowsolvent gas concentration and then to the outside of the capacitor.

When only a short time passes, there is almost no difference between theweight reduction rates. This is considered to be because, similarly toembodiment 1, the activated carbon, which is adsorbent 9, adsorbs thesolvent gas and a certain time is needed until the solvent gasconcentration in sealing body 15 or first layer 18 becomes high.

Coating layer 7 of embodiment 1, and sealing bodies 15 and 15A ofembodiment 2 are particularly effective when a γ-butyrolactone andsulfolane solvent for high heat resistance is used as electrolyte 4.However, they may also be used when a general solvent such as water,ethylene glycol, propylene carbonate, ethylene carbonate, or dimethylcarbonate is used.

In the above description, an example of an electrolytic condenser as thecapacitor has been described; however, the invention is also applicableto other electrochemical elements using an electrolyte such as electricdouble layer capacitors or batteries.

INDUSTRIAL APPLICABILITY

With the capacitor of the present invention, it is possible to suppressdry up by suppressing gas permeation of a sealing body. Therefore, theinvention is particularly useful as a capacitor for use in fields thatrequire the use of a capacitor in a high-temperature environment.

REFERENCE MARKS IN THE DRAWINGS

-   1 CAPACITOR ELEMENT-   2 ANODE LEAD WIRE-   3 CATHODE LEAD WIRE-   4 ELECTROLYTE-   5 CASE-   6, 15, 15A SEALING BODY-   7 COATING LAYER-   8 RESIN-   9 ADSORBENT-   16 RUBBER COMPONENT-   18 FIRST LAYER-   19 SECOND LAYER

1. A capacitor comprising: a capacitor element; an electrolyte impregnated into the capacitor element; a bottomed cylindrical metal case accommodating the capacitor element and the electrolyte; a sealing body sealing an opening portion of the case; and a coating layer provided at a portion in contact with an outer surface of the sealing body and formed by dispersing, into resin, an adsorbent adsorbing a solvent included in the electrolyte.
 2. The capacitor according to claim 1, wherein the adsorbent is at least any one of activated carbon, zeolite, molecular sieve, and silica gel.
 3. The capacitor according to claim 1, wherein the resin configuring the coating layer is at least any one of epoxy resin, fluorine resin, acrylic resin, polyimide resin, silicone resin, phenol resin, melamine resin, urethane resin, and unsaturated polyester resin.
 4. The capacitor according to claim 1, wherein a ratio of the adsorbent is 6% by volume or more and 33% by volume or less of the coating layer.
 5. A capacitor comprising: a capacitor element; an electrolyte impregnated into the capacitor element; a bottomed cylindrical metal case accommodating the capacitor element and the electrolyte; and a sealing body sealing an opening portion of the case; wherein the sealing body is formed by dispersing an adsorbent, which adsorbs a solvent included in the electrolyte, in a rubber component.
 6. The capacitor according to claim 5, wherein the adsorbent is at least any one of activated carbon, zeolite, molecular sieve, and silica gel.
 7. The capacitor according to claim 5, wherein the rubber component forming the sealing body is any of butyl rubber, ethylene propylene rubber, fluorine rubber, silicone rubber, nitrile rubber, or acrylic rubber.
 8. The capacitor according to claim 5, wherein a ratio of the adsorbent is 8% by volume or more and 40% by volume or less of the rubber component configuring the sealing body.
 9. The capacitor according to claim 5, wherein the sealing body includes a first layer facing an outer face of the capacitor and a second layer facing an inner face of the case, and the adsorbent is dispersed in a greater amount into the first layer than into the second layer. 